Conventionally, in a semiconductor device manufacturing field, there is known a plasma processing apparatus using inductively coupled plasma (ICP) as an apparatus for performing a process such as a film forming process or an etching process on a substrate such as a semiconductor wafer.
In a plasma processing apparatus having a high frequency coil provided above an upper portion of a processing chamber, as a processing gas supply structure of the plasma processing apparatus using ICP, a processing gas supply device of an annular hollow pipe is provided around a substrate, i.e., in a space between the high frequency coil and the substrate. Further, a processing gas is discharged into a space above the substrate from a multiple number of gas discharge openings formed at an inner periphery of the hollow pipe (for example, see Patent Document 1).
Meanwhile, in a plasma processing apparatus having a high frequency coil provided at a sidewall of a processing chamber, for example, a processing gas is discharged from an upper center of the processing chamber to a space above a substrate (for example, see Patent Document 2).
As the above-described processing gas supply structures, a nozzle type structure having holes or slits is used. In the plasma processing apparatus having the high frequency coil provided above the upper portion of the processing chamber, if there exists a large structure for introducing the gas to above the substrate, the substrate are blocked by the large structure, so that a non-uniform process on the substrate may be performed. Meanwhile, if a gas diffusion space is provided above the substrate and below the high frequency coil, a means to prevent an electric discharge in this space may be needed. For this reason, a region for discharging a gas is basically limited to a central portion and an outer peripheral portion of the substrate.
Patent Document 1: Japanese Patent Laid-open Publication No. 2001-085413
Patent Document 2: Japanese Patent No. 3845154
As described above, in the conventional plasma processing apparatus and the processing gas supply structure thereof, since the region for discharging a gas is limited, it may be difficult to improve uniformity of a process on a substrate surface by controlling a supply of the processing gas.